﻿286 
  Messrs. 
  Gill 
  and 
  Pidduck 
  on 
  the 
  Genesis 
  of 
  Ions 
  

  

  for 
  the 
  unpurified 
  helium 
  are 
  appended. 
  The 
  corresponding- 
  

   curves 
  for 
  hydrogen 
  are 
  given 
  in 
  these 
  diagrams, 
  as 
  this 
  

  

  Fig-. 
  3. 
  — 
  Helium. 
  

  

  2-0 
  

  

  

  

  , 
  

  

  

  

  

  

  s' 
  / 
  

  

  

  

  y 
  

  

  Y 
  /'' 
  

  

  / 
  

  

  

  

  

  / 
  

  

  

  

  

  / 
  

  

  

  

  

  

  •05 
  

  

  100 
  150 
  

  

  Fig. 
  4. 
  — 
  Helium. 
  

  

  200 
  

  

  

  

  

  

  

  

  

  

  

  

  P 
  

  

  

  // 
  

  

  / 
  

  

  / 
  

  

  

  

  HY 
  D 
  Jl~' 
  

  

  / 
  

  

  

  50 
  

  

  100 
  

  

  ISO 
  

  

  200 
  

  

  gas 
  most 
  nearly 
  approaches 
  helium 
  in 
  its 
  behaviour 
  in 
  this 
  

   respect. 
  It 
  is 
  thus 
  seen 
  from 
  these 
  curves 
  that 
  both 
  positive 
  

   and 
  negative 
  ions 
  ionize 
  the 
  molecules 
  of 
  helium 
  to 
  a 
  greater 
  

   extent 
  than 
  the 
  molecules 
  of 
  other 
  gases 
  when 
  small 
  electric 
  

   forces 
  are 
  acting. 
  

  

  